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hw_breakpoint: fix single-stepping when using bpf_overflow_handler
[ Upstream commit d11a698 ] Arm platforms use is_default_overflow_handler() to determine if the hw_breakpoint code should single-step over the breakpoint trigger or let the custom handler deal with it. Since bpf_overflow_handler() currently isn't recognized as a default handler, attaching a BPF program to a PERF_TYPE_BREAKPOINT event causes it to keep firing (the instruction triggering the data abort exception is never skipped). For example: # bpftrace -e 'watchpoint:0x10000:4:w { print("hit") }' -c ./test Attaching 1 probe... hit hit [...] ^C (./test performs a single 4-byte store to 0x10000) This patch replaces the check with uses_default_overflow_handler(), which accounts for the bpf_overflow_handler() case by also testing if one of the perf_event_output functions gets invoked indirectly, via orig_default_handler. Signed-off-by: Tomislav Novak <tnovak@meta.com> Tested-by: Samuel Gosselin <sgosselin@google.com> # arm64 Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/linux-arm-kernel/20220923203644.2731604-1-tnovak@fb.com/ Link: https://lore.kernel.org/r/20230605191923.1219974-1-tnovak@meta.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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